The present invention relates to a method for changing a guide width and a mechanism for changing a guide width and, more particularly, to a method and a mechanism for changing a guide width of a width guide so that a photosensitive material can be guided properly with respect to width direction thereof in a conveyance course of photosensitive materials in a photo-processing apparatus.
The conventional width guide, as shown in FIG. 6 for example, comprises a pair of V-shaped members 51 guiding both side edges of a photosensitive material P and a screw shaft 52. A distance between the members 51 is adjusted by turning the screw shaft 52 to move both or one of V-shaped members. It is also known to use a rack and pinion (not illustrated) for moving the V-shaped members.
Width of the width guide is fitted to a width of a photosensitive material to be treated by turning the screw shaft of the width guide or the pinion with a operator's hand, or a motor and the like.
In the concrete, a width of a width guide is adjusted by inserting a photosensitive material to be treated into a first width guide, looking at a clearance between the width guide and an edge of a photosensitive material and moving the width guide by a manual or electromotive operation.
It takes, however, a long time and requires complicated operations to adjust each width guide one by one according to a photosensitive material every time a photosensitive material is changed, since many width guides are provided in a photo-processing apparatus along a conveyance course of photosensitive material.
Thus, there has been employed a method as a simple method wherein a width of a width guide for every nominal size of a photosensitive material (e.g. 89 mm, 127 mm) is predetermined and the width guide is automatically moved to a directed position by directing a nominal size of a photosensitive material to be treated.
Recently, in addition to increase in numbers of size of photosensitive materials, there are some differences in true widths thereof depending upon manufacturers even if they are of the same nominal size.
Therefore, according to the above conventional method, since a width of a width guide corresponds to a nominal size only one to one, a photosensitive material cannot be conveyed because of deviation from the width guide when the real width of the photosensitive material is narrower than a predetermined guide width, while the photosensitive material cannot be conveyed because of catching by the width guide when the real width of the photosensitive material is wider than a predetermined guide width.
In that case, since a guide board adapted to a width of a photosensitive material to be treated must be prepared and exchanged one by one, operating cost of the apparatus rises sharply.
It is an object of the present invention to solve the above problems and to provide a method and a mechanism for automatically changing a width of a width guide depending upon photosensitive materials which differ from each other in true width even though they have the same nominal size.